Python assert语句的简单使用示例

if not expression:
 raise AssertionError

>>> assert True
>>> assert False
Traceback (most recent call last):
 File "<pyshell#3>", line 1, in <module>
 assert False
AssertionError

>>> assert 1==1
>>> assert 1==0
Traceback (most recent call last):
 File "<pyshell#1>", line 1, in <module>
 assert 1==0
AssertionError

>>> assert [1, 2] # 非空列表值得注意一下，虽说也没个啥，哈哈
>>> assert not [1, 2]
Traceback (most recent call last):
 File "<ipython-input-48-eae410664122>", line 1, in <module>
 assert not [1, 2]
AssertionError

>>> assert None, 'None若作为布尔表达式，则相当于False'
>>> assert [], '空列表若作为布尔表达式，则相当于False'
>>> assert (), '空元组若作为布尔表达式，则相当于False'
>>> assert {}, '空字典若作为布尔表达式，则相当于False'
>>> assert set(), '空集合若作为布尔表达式，则相当于False'
>>> assert '', '空字符串若作为布尔表达式，则相当于False'

>>> a = np.array([1, 2])
>>> assert a 
Traceback (most recent call last):

 File "<ipython-input-45-63e954d94e9b>", line 1, in <module>
 assert aa

ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()

>>> assert np.array([])
>>> assert np.array([[], []])